KR20110122617A - Method and apparatus for recording channel measurement information in mobile communication system - Google Patents

Abstract

The present invention relates to a method and apparatus for efficiently configuring information in a process of recording channel measurement information by a terminal in a mobile communication system.
The present invention discloses a terminal operation for accurately informing a base station whether a serving cell or neighbor cells are measured in the configuration of channel measurement information. In addition, the terminal proposes a method of adjusting the recording frequency in consideration of the importance of the measurement information.

Description

TECHNICAL AND APPARATUS FOR LOGGING A CHANNEL MEASUREMENT INFORMTAION IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a method and apparatus for efficiently configuring information in a process of recording channel measurement information by a terminal in a mobile communication system. More specifically, the present invention discloses a terminal operation for accurately informing a base station whether a serving cell or neighbor cells are measured in the configuration of channel measurement information. In addition, the terminal proposes a method of adjusting the recording frequency in consideration of the importance of the measurement information.

In general, a mobile communication system has been developed for the purpose of providing communication while securing user mobility. Such a mobile communication system has reached a stage capable of providing high-speed data communication service as well as voice communication due to the rapid development of technology. Recently, as a next-generation mobile communication system, 3GPP is working on specifications for Long Term Evolution-Advanced (LTE-A). LTE-A is a technology that implements high-speed packet-based communication with a higher transmission rate than the currently provided data rate, with the aim of completing the standard in late 2010.

As the 3GPP standard evolves, there are discussions on how to easily optimize the wireless network in addition to increasing the communication speed. In general, during the initial construction of a wireless network or network optimization, a base station or a base station control station should collect radio environment information on its cell coverage, which is called a drive test. Conventional drive tests have often been cumbersome in that measurement equipment is loaded on a vehicle and repeated measurement tasks are performed for a long time. The measured result is used to set system parameters of each base station or base station control station through an analysis process. Drive testing like this increases wireless network optimization and operating costs, and can be time consuming. Therefore, researches for minimizing the drive test and improving the analysis process and the manual setting for the wireless environment are being conducted under the name of the Minimization of Drive Test (MDT). For this purpose, instead of the drive test, the terminal performs channel measurement and periodically or when a specific event occurs, immediately transmits the corresponding channel measurement information to the base station, or after a certain time elapses after storing the channel measurement information to the base station. To pass. Hereinafter, the operation of transmitting the channel measurement information measured by the terminal to the base station may be referred to as channel measurement information report or MDT measurement information report. In this case, the terminal may transmit the channel measurement result to the base station immediately if communication with the base station is possible. Otherwise, the terminal stores the report and reports the result to the base station when communication is possible later. The base station then uses the channel measurement information received from the terminal for cell area optimization. In LTE-A, the basic MDT measurement information reporting operation is classified according to the UE RRC state as shown in Table 1 below.

RRC state of the terminal

MDT measurement information report operation of terminal
Idle mode

After recording, report
(logging and deferred reporting)

Connected mode

Immediate reporting
Connected mode

After recording, report
(logging and deferred reporting)

Table 1 shows a basic MDT information reporting operation according to the RRC state of the terminal.

In Table 1, the state in which the terminal is not communicating with the base station is called an idle mode, and otherwise, it is called a connected mode. In the case of MDT, since the channel information measured by the terminal will be transmitted by RRC signaling, even if the terminal is in the idle mode, the terminal cannot be changed to the connected mode to transmit the corresponding information. In this case, the terminal only records the channel measurement information and defers the transmission until it changes to the connection mode with the base station.

Meanwhile, even in the connected mode, the terminal may directly send channel measurement information to the base station according to the situation, but in the idle mode, the terminal may record the measurement information, and later, the terminal may transmit the recorded information after the terminal is in the connected mode. The base station requests the measurement information report from the corresponding terminal, and thus the terminal sends the recorded measurement information.

The terminal in the idle mode records channel measurement information when the measured information satisfies a specific event or periodically. One embodiment of an event for recording channel measurement information is described below.

(1) Periodic downlink pilot measurements

(2) Serving cell becomes worse than threshold

(3) Transmit power headroom becomes less than threshold

(4) Paging Channel Failure

(5) Broadcast Channel failure

(6) Random access failure

(7) Radio link failure report

The MDT measurement and recording information construction method is expected to be defined with reference to the existing RRC measurement method. However, unlike the existing RRC measurement method performed on the premise of the existence of the serving cell, MDT measurement is performed regardless of the existence of the serving cell. Because the MDT measurement information will be used for cell area optimization rather than mobility support, the terminal should measure signals from base stations around the terminal even in a coverage hole. The measurement result report in the RRC measurement method includes a serving cell measurement result and a neighbor cell measurement result. However, if the configuration is applied to the MDT measurement report as it is, as described above, in some cases, the serving cell information result cannot be recorded, which may cause confusion. Therefore, a clear definition of this is needed.

The conventional RRC measurement method has an algorithm for limiting the range of cells to be measured in order to minimize power consumption of the terminal in the idle mode. The purpose of the RRC measurement is to determine the signal status of the neighboring cell as well as the serving cell so that the UE can be connected to a cell providing good quality. If the state of the serving cell does not meet certain criteria and the neighbor cell provides better signal quality, the terminal will attempt to connect to the cell. However, if the serving cell can provide a good signal quality over a certain criterion, it is not necessary to determine the signal state of the neighboring cell while consuming the power of the terminal. Therefore, in the RRC measurement, if the signal strength from the serving cell is good over a predetermined reference, the adjacent cell signal is not measured. The terminal selects adjacent cells to be measured step by step using two thresholds, Sintrasearch and Snonintrasearch.

1 illustrates an operation of measuring a terminal in an idle mode according to two thresholds. If the reference signal received power (RSP, 115) of the serving cell is greater than Sintrasearch 105, the UE does not measure the signal of the neighbor cell. This is because current serving cells can provide a signal of sufficiently good quality. On the other hand, if the RSRP of the serving cell is less than or equal to Sintrasearch 105, and greater than Snonintrasearch 110, the terminal measures the signal of the adjacent cell having the same frequency as the serving cell. And if the RSRP of the serving cell is less than Snonintrasearch 110, the terminal measures all the signals of cells belonging to different frequencies and other systems.

The MDT measurement will be defined similarly to the existing RRC measurement method, and in order to reduce the power consumption of the terminal, the above two thresholds of Sintrasearch and Snonintrasearch will be applied. However, since MDT measurement is focused on cell area optimization, not mobility support, it is necessary to know why there is no measurement result of neighboring cells in recording unlike conventional RRC measurement. That is, information on whether the signal strength of the serving cell is large and there is no measurement result or the signal of the actual neighboring cell is not measured is necessary.

On the other hand, location information is an important factor in MDT measurement. When GPS-based location information is not obtained, a set of signal strengths received from neighboring base stations is measured and reported to the base station. The base station calculates an approximate measurement position using techniques such as triangulation and aggregation information of the signal strength received from the terminal. If the RSRP of the serving cell is larger than Sintrasearch, the neighboring cell cannot be measured, and thus the set of signal strengths of the neighboring cells to be used for location information cannot be measured and recorded. At this time, since the usefulness of the MDT measurement whose location information is unknown will be inferior, it may not be desirable to increase the terminal and signaling overhead due to periodic recording.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method and apparatus for efficiently configuring channel measurement information by a terminal. In particular, it is an object of the present invention to provide a method and apparatus for reporting the presence or absence of measurement for a serving cell or neighbor cells in a channel measurement information configuration and adjusting a recording frequency.

In the mobile communication system of the present invention for solving the above problems, the method for recording channel measurement information of a terminal includes receiving channel configuration information for receiving the measurement configuration information for measuring the channel from a base station, and serving cell according to the measurement configuration information. And a measuring step of measuring a neighboring cell and a recording step of recording channel measurement information according to at least one criterion of the presence or absence of the serving cell and the presence or absence of the measurement of the neighboring cell.

In addition, the apparatus for recording channel measurement information in the mobile communication system of the present invention controls the measuring device to measure the serving cell and the neighboring cell according to the measuring device for measuring the serving cell and the neighboring cell, the channel configuration information received from the base station And a controller for controlling to record channel measurement information according to at least one of the presence of the serving cell and the measurement of the neighboring cell, and a buffer for storing the recorded channel measurement information.

According to the present invention, after performing channel measurement, the terminal can more accurately report information on whether the serving cell is measured or whether the neighbor cell is measured to the base station.

1 is a diagram illustrating an operation of measuring a terminal in an idle mode according to two thresholds. FIG. 2 illustrates a process in which a terminal 205 is instructed to perform an MDT from a base station 210 to report information recorded by measuring a channel. Flowchart.
3 is a flowchart illustrating an operation flow of a terminal in which a terminal reports a battery state to a base station for MDT measurement setup;
4 is a flowchart illustrating a process of performing MDT measurement by a terminal according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating an operation of a terminal when using a format that does not separately include a measurement result for a serving cell in the MDT measurement result. FIG.
6 is a flowchart illustrating a process of performing a MDT of a terminal according to whether a neighbor cell measurement result is present.
FIG. 7 is a flowchart illustrating an operation of a terminal to perform logging more frequently when a neighbor cell measurement result exists according to another embodiment of the present invention. FIG.
8 is a diagram for explaining timing of operating a GNSS receiver when a terminal enters a service range.
9 is a view for explaining a method of pre-operating a GNSS receiver before S-criterion, that is, at SGNSS-criterion.
10 is a block diagram illustrating an internal structure of a terminal for configuring MDT measurement information according to an embodiment of the present invention.

The present invention relates to a method and apparatus for efficiently configuring information in a process of recording channel measurement information by a terminal in a mobile communication system. The present invention discloses a terminal operation for accurately informing a base station whether a serving cell or neighbor cells are measured in the configuration of channel measurement information. In addition, the terminal proposes a method of adjusting the recording frequency in consideration of the importance of the measurement information.

2 is a flowchart illustrating a process in which the terminal 205 is instructed to perform an MDT from the base station 210 and reports the recorded information by measuring a channel.

In step 215, the terminal 205 is changed to the connected mode state for communication with the base station 210. In step 217, the terminal 217 may inform the base station 210 of the UE capability or the UE status of the terminal according to the request of the base station 210. The terminal capability, such as the presence or absence of GPS, may be referred to in determining whether the base station 210 indicates the MDT to the corresponding terminal. In addition, the current state of the terminal 205 can be reported so that the MDT instruction can be referred to. For example of the current status report of the terminal, as shown in Equation 1 below, when the base station requests, the terminal may report the amount of power remaining (that is, the battery state) to the base station 210.

[Equation 1]

UE information response = [current battery status, average battery consumption during the last x hours]

In Equation 1, 'current battery status' means the current terminal power remaining. Another value, 'average battery consumption during the last x hours', represents the average power consumption of the terminal during the last x hours. This value refers to the strategy consumption rate of the terminal 205 in the near past, and the base station can predict the power usage pattern of the terminal and use it to predict the remaining service time in the future.

In step 220, if the base station 210 determines that the MDT measurement is necessary in the idle mode, the base station 210 performs MDT configuration. That is, the measurement configuration information necessary for the MDT measurement is transmitted to the terminal 205. Thereafter, the terminal 205 enters the idle mode in step 225. When the terminal 205 enters the idle mode, the MDT measurement starts in step 230.

MDT is performed for the purpose of initial construction and optimization of the wireless network for the purpose. Therefore, it only needs to be performed for a certain period of time. Therefore, the base station 210 needs to instruct the terminal 205 of the MDT measurement execution time during the MDT configuration process. When the terminal 205 is in the connected mode, the base station 210 may signal the terminal 205 to the measurement stop time accurately. However, if the terminal 205 is in the idle mode, the base station 210 cannot inform the terminal 205 of the stopping time through signaling, so it informs the timer information in advance, and stops the MDT measurement when the timer expires. You can. Therefore, the terminal 205 operation immediately stops the MDT measurement when the signaling to stop the MDT measurement in the connected mode before the timer expires, and if the stop signaling is not received, the measurement continues, The measurement stops at step 245 at which point the timer expires. The terminal 205 periodically records the information measured in step 235 during the MDT measurement interval. Alternatively, when the specific condition is satisfied, the information measured in step 240 is recorded.

The terminal 205 stops the MDT measurement in step 245 after the indicated execution period ends.

Thereafter, the terminal 205 determines to switch to the connected mode in step 250. The terminal 205 switched to the connected mode may transmit the channel measurement information recorded in the idle mode to the base station 210. Before the transfer, the terminal 205 includes the state information on the channel measurement information recorded in step 255 in the RRC connection setup complete message (RRCConnectionSetupComplete). In this case, it is not preferable to include too much information in the state information transmitted from the terminal 205 to the base station 210. Therefore, only necessary state information should be delivered. For example, by using two bits, the terminal 205 may inform whether the MDT is in progress and whether there is any record information to complete and report the MDT. The reason for sending the index information is to inform the base station 210 of what channel measurement information is being recorded by the terminal 205, and whether the base station 210 transmits the channel measurement information using the received status information. To provide a basis for judgment so that the request can be determined.

For example, if terminal 205 is in idle mode for a long time, a large amount of channel measurement information will be recorded. At this time, when switched to the connected mode, the terminal 205 must consume a lot of resources for transmitting the record information. In order to solve this problem, the base station 210 checks and requests necessary information in advance.

If the base station 210 determines that the channel measurement information recorded by the terminal 205 is useful, the base station 210 requests the MDT measurement information through a terminal information request message (UEInformationRequest) in step 260 at an appropriate timing. When the terminal 205 receives a request for terminal information from the base station 210, if all DRBs for general data are released, the terminal 205 transmits MDT measurement information to the base station 210 in step 265. This means that the priority for general data transmission is higher than the priority for transmission of measurement information. This is generally because the recorded measurement information is less urgently transmitted. Alternatively, a new RB (Radio Bearer) with a lower priority may be created and used to transmit MDT measurement information. In step 270, the terminal 205 transmits the MDT measurement information to the base station 210 by including the terminal information response message (UEInformationResponse).

 In the MDT measurement information transmission process as shown in FIG. 2, the information configuration for channel measurement is expected to be defined with reference to the existing RRC measurement. At this time, in order to improve the suitability and performance of the MDT support, in the case of the MDT measurement information configuration, the matters to be different from the information configuration in the RRC measurement are summarized as follows.

1) If there is no serving cell measurement information, configure information to inform

2) Configuration of information that can inform the presence or absence of the measurement of the adjacent cell signal according to the signal strength of the serving cell

3) how to control the frequency of recording less useful information

In this patent, in order to consider the above-described matters, the terminal operation is defined and an information configuration format is proposed.

If the MDT measurement result is configured similarly to the existing RRC measurement result, the MDT measurement result is composed of the following information.

MDT measurement result = [measurement result of serving cell, measurement result of neighboring cell, ECGI of serving cell, other information]

The measurement result of the serving cell is a value obtained by measuring signal strength of a predetermined signal such as a common pilot signal of the serving cell. The measurement results of the neighboring cells are a set of predetermined number of neighboring cell measurement results in order of signal strength. The peripheral cell measurement result may consist of the following information.

Measurement result of neighboring cell = [Physical layer cell identifier (PCI, Physical Cell Id) of corresponding cell, signal strength of predetermined signal of corresponding cell]

The EUTRAN Cell Global Id (ECGI) for the serving cell is an identifier of a cell provided as system information, and a network device such as an MDT server can clearly identify the cell using the ECGI.

The MDT server or the like may perform cell optimization using the MDT measurement result provided by the UE (that is, the measurement result of the serving cell, the measurement result of the neighboring cell, the ECGI of the serving cell, and other information).

At this time, the MDT server or the like may determine the presence of a shadow hole, for example, using the measurement result of the serving cell and the measurement result of the neighboring cell. The MDT server and the like may determine the location of the shadow area by using the ECGI of the serving cell and the measurement result of the serving cell and the neighboring cell. The positional information can be grasped by so-called triangulation. For example, based on the absolute position of the cell corresponding to the ECGI, the neighboring cell having the PCI corresponding to the PCI reported as the neighbor cell measurement result value from the MDT measurement result among the neighboring cells of the cell whose absolute position is determined is selected. Triangulation is then performed using the signal strength measurement results of the selected neighboring cells.

Meanwhile, the terminal may be configured to perform periodic MDT measurement in an idle state and to record (or log, which is the same below) the measurement result. For example, when the MDT measurement is set and then transitions to an idle state at an arbitrary time point, the UE measures the signal strengths of the serving cell and the neighboring cell at predetermined time points determined by a preset period and logs the value according to a predetermined format. .

However, there may be a case where the serving cell does not exist at the time when the MDT measurement should be performed. At this time, if the MDT measurement result does not include the measurement result of the serving cell and ECGI information of the serving cell, there is a problem that the MDT server cannot estimate the location where the measurement result is logged. A criterion for selecting a serving cell is a cell whose signal strength is greater than or equal to a predetermined reference value and which has the best channel state among the cells whose access to the cell is not prohibited. Therefore, at any point in time, if there is no cell whose signal strength is greater than or equal to a predetermined reference value (see S-criteria 36.304) or if all cells are prohibited from accessing, the serving cell may not exist.

In the present invention, in the situation where the serving cell does not exist as described above, the reason why the serving cell does not exist is because there is no cell whose signal strength satisfies a predetermined reference value (S-criteria) (Indication 1), Alternatively, information indicating whether all cells satisfying S-criteria are prohibited cells (indication 2) is included in the MDT measurement result, which will be described in detail later.

3 is a flowchart illustrating an operation flow of a terminal in which a terminal reports a battery state to a base station for MDT measurement setup. In this case, the operation process of the terminal illustrated in FIG. 3 may be a process specifically illustrating a process in which the terminal 205 of step 217 of FIG. 2 reports the terminal state (here, the battery state of the terminal) to the base station 210. have.

In step 305, the terminal receives a control message for commanding the battery status report from the base station. The control message may be used by extending, for example, a UEInformationRequest message defined in 36.331. For example, an indicator indicating whether to request a battery status report may be newly defined and used in the message.

In step 310, the terminal determines remaining battery power at the corresponding time to configure the remaining battery power information (remaining battery power). At this point in time, the battery consumption until a predetermined time period (for example, n hours) is determined. The information may be a total of battery consumption for the predetermined predetermined period or may be an average battery consumption. The battery power consumption is used to configure battery power consumption during the last predefined period information. In step 315, the terminal generates a predetermined RRC message including the remaining battery power information and battery power consumption during the last predefined period information. The RRC message may be a UE information response message (UEInformationResponse message) defined in 36.331.

In step 320, the UE transmits the RRC control message.

4 is a flowchart illustrating a process of a terminal performing MDT measurement according to an embodiment of the present invention.

First, when the terminal receives an MDT measurement configuration message (MDT measurement configuration) from the base station in step 405, the terminal sets the MDT measurement. If the MDT measurement is set to be performed in the idle state, the terminal waits until the RRC connection is released and then proceeds to step 410 to start the MDT measurement.

The MDT measurement may be, for example, periodically measuring and logging the signal strength of a cell (a serving cell or a neighboring cell). When it is time to perform the MDT measurement, the UE checks whether there is a serving cell at that time in step 415. If it exists, the flow proceeds to step 430 to measure the signal strength of the serving cell and the neighboring cell and records the result in the MDT measurement result. In step 435, the terminal records the ECGI of the serving cell in the measurement result.

On the other hand, if it is determined in step 415 that the serving cell does not exist, the flow proceeds to step 420 where there is no serving cell. Check for this. If so, the UE proceeds to step 440 and sets the serving cell absence indicator (or indication 1, hereinafter same) to YES and the access barring cell indicator (or indication 2, hereinafter same) for the corresponding MDT measurement result. Set it.

On the other hand, if there is a cell that satisfies the s-criteria, but if there is no serving cell, the terminal proceeds to step 425, and checks whether all cells satisfying the s-criteria are access inhibited cells. Whether or not the access is prohibited is determined by analyzing the access prohibited information provided through the system information. If all cells satisfying the s-criteria are the access inhibited cells in step 425, the terminal proceeds to step 445 and sets indication 1 to no and indication 2 to yes.

In step 450, the terminal records the measurement result value of the neighboring cell in the MDT measurement result. In step 455, the UE selects one of the neighbor cells and records the ECGI of the cell in the MDT measurement result. The peripheral cell to write the ECGI may be, for example, the peripheral cell having the strongest signal strength. Alternatively, the terminal may be a neighbor cell in which the UE has already obtained ECGI. In the latter case, the UE records information indicating which neighboring cell the ECGI corresponds to, that is, PCI corresponding to the ECGI.

In step 460, the terminal records the number of cells that measured the signal strength at the corresponding time point and terminates the MDT measurement result recording process at the corresponding time point. Measuring any cell at any point in time also means that the cell has been detected. Therefore, in step 460, the terminal may be expressed as recording the number of detected cells at the corresponding time.

The reason for recording the number of detected cells together is as follows. In the idle state, the UE continuously performs measurement on the serving cell, and performs measurement only when the channel state of the serving cell deteriorates to a predetermined reference or less for the neighboring cell. In other words, if the channel state of the serving cell is good enough, the surrounding cell measurement result itself may not exist. Therefore, if the MDT measurement results recorded at any point in time do not contain the neighbor cell measurement results or if there are only the neighbor cell measurement results smaller than the number originally reported, this means that the serving cell has a good channel state and thus no neighbor cell measurement has been made. Alternatively, it may be because a relatively recent amount of neighboring cell measurement results are not yet present, or because the number of neighboring cells actually detected is small.

A network device that has performed a necessary operation by analyzing an MDT measurement result such as an MDT server can distinguish the two cases by using the number of detected cells. In step 460, the UE may set the neighbor cell measurement indicator (or indication 3, which is the same below) and record the result in the MDT measurement. indication 3 is an indicator indicating whether the channel state of the serving cell at that time is higher or lower than a reference value (see Sintrasearch or Sintersearch. In other words, the indication 3 is an indicator indicating whether the measurement of the neighboring cell at that time. The terminal may set the indication 3 to YES if the signal strength of the serving cell is higher than the reference value, that is, if the measurement of the neighboring cell has not been performed, and if the signal strength of the serving cell is lower than the reference value, the indication 3 may be set to NO. have.

In detail, MDT measurement results of the present invention are configured as follows.

MDT measurement result = [measurement result of serving cell, measurement result of neighboring cell, ECGI, PCI corresponding to ECGI, indication 1, indication 2, indication 3, number of detected cells]

The ECGI is the ECGI of the serving cell or the ECGI of the cell corresponding to the PCI indicated in the PCI corresponding to the ECGI if the serving cell does not exist.

indication 1 and indication 2 are used when there is no serving cell. Detailed usage is already explained, and thus the description is omitted.

The number of detected cells is also omitted.

Hereinafter, as an operation of a terminal according to another embodiment of the present invention for configuring the MDT measurement information, an operation in the case of using a format that does not separately include the measurement results for the serving cell in the MDT measurement results. In this case, the MDT measurement result is configured as follows.

MDT measurement result = [cell measurement results, ECGI, PCI corresponding PCI, indication 1, indication 2, indication 3, indication 4, number of cells detected]

The serving cell presence indicator (or indication 4, which is the same below) is an indicator indicating whether the serving cell exists in the terminal at the time when the MDT measurement result is logged.

Referring to Figure 5 will be described in more detail the operation in the case of using a format that does not separately include the measurement results for the serving cell in the MDT measurement results.

First, when the terminal receives an MDT measurement configuration message (MDT measurement configuration) from the base station in step 505, the terminal sets the MDT measurement. If the MDT measurement is set to perform in the idle state, the UE waits until the RRC connection is released and then starts the MDT measurement in step 510. The MDT measurement may be, for example, periodically measuring and recording the signal strength of the cell.

When the UE arrives at the point in time 515 to perform the MDT measurement, the UE records the measurement results of the n cells having the best signal strength among the cells detected at the time point in the MDT measurement result. The terminal proceeds to step 520 to select a cell to record the ECGI. When selecting a cell for ECGI recording, the UE may select a cell that already knows the ECGI at that time. Since the ECGI is obtained through system information, the cell that already knows the ECGI is likely to be a serving cell at that time. If the serving cell does not exist at that time, the UE may attempt to acquire ECGI from the cells having the best signal strength at that time, and select a cell that successfully acquires ECGI as a cell to record ECGI.

In step 525, the UE records the ECGI of the selected cell and the PCI of the cell in the MDT measurement result. In step 530, the UE sets indication 1, indication 2, indication 3, and indication 4. indication 4 is an indicator of whether there is a serving cell at a corresponding time, and the terminal sets indication 4 to NO if there is a serving cell. In step 535, the UE records the number of detected cells and ends the MDT measurement result recording operation.

As described above, the network device may estimate the position where the UE performed the MDT measurement by using the neighbor cell measurement result of the MDT measurement result and the ECGI. However, there is a case where the serving cell channel state is good at that time, that is, the signal strength of the serving cell is higher than a reference value such as Sintrasearch or Sintersearch, so that measurement is not performed on neighboring cells. In this case, the UE may log only the measurement result of the serving cell, but the utility of the MDT measurement result without the neighbor cell measurement result is low. Therefore, the present invention checks whether there is a neighbor cell measurement result at the time of logging the MDT measurement result, if there is no neighbor cell measurement result, logging is performed at a longer period, and if there is a neighbor cell measurement result, logging is shorter. It suggests how to perform the cycle.

6 is a flowchart illustrating a process of performing MDT of a terminal according to whether a neighbor cell measurement result is present.

First, in step 605, the terminal sets the MDT measurement when receiving the MDT measurement configuration message from the base station. The MDT measurement configuration message may include, for example, information on an MDT logging cycle. The logging period may be given as a plurality of periods including a long period and a short period. The long period may be applied when there is no neighbor cell measurement result, and the short period may be applied when there is a neighbor cell measurement result. .

When the RRC connection is released, the UE waits for a predetermined period of time in step 610, and then proceeds to step 615 to start initial logging. In general, when the RRC connection is released, the UE starts measuring neighbor cells in order to select a serving cell. The MDT logging is preferably started after the terminal performs the measurement as much as possible to ensure the proper reliability in the idle state. Therefore, the terminal does not start MDT logging as soon as it transitions to the idle state, but waits for a predetermined period and then performs the first MDT logging in step 615. According to an embodiment of the present invention, the predetermined period may be expressed as a multiple of the DRX cycle of the terminal. Thereafter, the terminal periodically repeats MDT logging according to a predetermined cycle.

After performing the first MDT logging, the terminal proceeds to step 620 and waits until the next MDT logging time. The next MDT logging time point may be determined by the MDT logging period set through the MDT measurement configuration message. In short, the [n + 1] th logging time starts after the MDT logging cycle flows from the nth logging time. The MDT logging period may be a long period or a short period depending on the signal strength of the serving cell. In other words, if the signal strength of the serving cell is equal to or greater than a predetermined reference value, a long term period is applied. When the terminal reaches the next MDT logging time, the terminal proceeds to step 625 to perform MDT logging and returns to step 620 to repeat the MDT logging operation.

FIG. 7 is a flowchart illustrating an operation of a terminal to perform logging more frequently when a neighbor cell measurement result exists according to another embodiment of the present invention.

First, in step 705, the terminal sets the MDT measurement when receiving the MDT measurement configuration message from the base station. The configuration message may include, for example, information on an MDT logging cycle. The UE waits for a predetermined period when the RRC connection is released.

When the first logging time arrives in step 715, the terminal proceeds to step 720 and initializes the counter (COUNTER) to zero. In step 725, the terminal checks whether a neighbor cell measurement result exists at the first logging time. Alternatively, it may be checked whether the signal strength of the serving cell is equal to or less than a predetermined reference value at the first logging time.

If there is a neighbor cell measurement result or the signal of the serving cell is less than a predetermined reference value, the terminal proceeds to step 740 and performs MDT logging.

On the other hand, if the neighbor cell measurement results do not exist in step 725 or the signal strength of the serving cell is greater than the predetermined reference value, the terminal proceeds to step 730 and increases the counter by one. In step 735, the terminal checks whether the COUNTER is greater than or equal to a predetermined reference value. The COUNTER is a value that is incremented by 1 each time the UE omits MDT logging, so that the COUNTER is greater than or equal to a predetermined reference value means that the MDT logging is omitted continuously over a predetermined reference value, and the MDT logging is omitted for an excessively long time. In order to prevent the terminal from proceeding, the terminal proceeds to step 740 and performs MDT logging. If the COUNTER is smaller than a predetermined reference value, it means that the MDT logging can be omitted, and the terminal proceeds to step 745 to skip the MDT logging and waits until the next logging time.

In order to simplify the operation of the terminal, the operation may be changed by performing MDT logging only when there are neighbor cell measurement results or information indicating the location of the terminal. That is, when the logging time is reached, the UE checks whether there are neighbor cell measurement results (or other information for estimating the location of the UE) at that time, and if so, performs MDT logging, and if not, MDT logging. May be omitted.

Meanwhile, according to a preferred embodiment of the present invention, the MDT measurement result reported by the terminal to the base station may include location information. In particular, when using a Global Navigation Satellite System (GNSS), the terminal may obtain accurate location information. However, even if the terminal has a GNSS receiver, the GNSS receiver is not always operated to prevent waste of power. In order to include the GNSS location information in the MDT measurement result, the GNSS receiver must be operated at an appropriate timing. For the main purpose of the MDT, the recorded location information is very useful when entering the service range. This is because it is a reference for estimating the location and size of the service range. When a reference signal received power (RSRP) value received from a specific cell is larger than a predetermined reference value RSRP (first reference value), the specific cell that transmits the reference signal may be defined as a serving cell. . Such a condition is referred to as an S-condition (hereinafter, 'S-criterion'). If this condition is not satisfied for 10 seconds, the terminal enters a cell selection (hereinafter, 'Any Cell Selection') state. In this state, since the terminal finds a serving cell or a cell for providing a limited service, it can be seen that the terminal is in a service range. Since the current serving cell does not satisfy the S-criterion and has 10 seconds to enter the 'Any Cell Selection' state, if the GNSS receiver is operated when the S-criterion is not satisfied, the terminal is in the service range When entering the terminal location will be obtained. With reference to FIG. 8, the timing of operating the GSNN receiver when the terminal enters the service range is described with reference to FIG. 8.

8 is a view for explaining the timing of operating the GNSS receiver when the terminal enters the service range. As shown in FIG. 8, the terminal is considered to move from left to right. It is assumed that the inside of the 805 region is the service transliteration region.

If the terminal enters the service range area 805, the current serving cell does not satisfy the S-criterion in step 810. If the S-criterion is not satisfied continuously for 10 seconds, the UE declares an 'Any Cell Selection' state in step 815.

The terminal operates the GNSS receiver to obtain location information when entering the service range region, that is, in step 810. The terminal acquires and records location information from its GNSS receiver for 10 seconds. Thereafter, the terminal stops the operation of the GNSS receiver to prevent power waste.

On the other hand, if the current serving cell again meets the S-criterion within 10 seconds, the terminal also stops the operation of the GNSS receiver.

In FIG. 8, if the terminal enters the service range region 805 and continues to the right to enter the service region, the terminal enters the serving cell satisfying the S-criterion after entering the service range region 805. You will find it again. That is, the terminal finds the serving cell in step 825. The UE starts the GNSS receiver again when the serving cell is found after the declaration of the 'Any Cell Selection' status. After a certain time, the terminal acquires and records location information in step 830.

Meanwhile, in the above-described embodiment, a time difference may occur until the GNSS receiver actually acquires location information after the UE operates the GNSS receiver. Accordingly, if the UE operates the GNSS receiver at the time when the current serving cell does not satisfy the S-criterion, it is guaranteed whether the GNSS receiver can actually operate and acquire location information until entering the 'Any Cell Selection' state. Can't.

Therefore, the terminal needs to operate the GNSS receiver before the S-criterion. In the present invention, the RSRP reference value (second reference value) larger than the RSRP reference value (first reference value) in the S-criterion may be defined in order to operate the GNSS receiver before the S-criterion. Since this new RSRP reference value (second reference value) will appear before the S-criterion of the terminal, the GNSS receiver can be operated before the terminal enters the service range, which is called SGNSS-criterion.

FIG. 9 is a view for explaining a method of operating the GNSS receiver in advance before S-criterion, that is, SGNSS-criterion.

If the UE enters close to the service range area 905, the serving cell will not satisfy the SGNSS-criterion in step 910. At this time, the terminal operates the GNSS receiver. Thereafter, in step 915, the serving cell does not satisfy the S-criterion, and in step 920, the serving cell will enter an 'Any Cell Selection' state. The UE acquires the location information by starting the GNSS receiver in step 925 before the 'Any Cell Selection' state. The time point at which the terminal acquires the location information is preferably at the time of entering the service range region 905.

after. The terminal stops the operation of the GNSS receiver to reduce power consumption. If the serving cell recovers the SGNSS-criterion before the 'Any Cell Selection' state, the GNSS location information acquisition operation is stopped. Thereafter, if the serving cell satisfies S'_GNSS-criterion, the GNSS receiver is operated in step 930. S'_GNSS-criterion has a lower RSRP reference value (third reference value) than the existing RSRP reference value (first reference value). This is because when the GNSS receiver needs to be operated before entering the service area when the service area area 905 enters the service area, the reference signal received power from a specific cell is lower than the original reference value (first reference value). It is because it should be defined as a serving cell at a close time even if the reference value 3) is satisfied.

The serving cell satisfies the S-criterion in step 935 and the terminal acquires location information in step 940 similarly to the corresponding time.

10 is a block diagram illustrating an internal structure of a terminal for configuring MDT measurement information according to an embodiment of the present invention.

The measurer 1005 measures signals from the serving cell and the adjacent cell.

The location information acquisition unit (or location information acquisition module) 1007 obtains location information of the terminal. According to a preferred embodiment of the present invention, the location information acquisition unit may be a Global Navigation Satellite System (GNSS) receiver.

The analysis and controller 1010 (or the controller, which is the same below) compares the signal strength of the serving cell with Sintrasearch and Snonintrasearch to determine whether to measure adjacent cells and to instruct the meter 1005 to measure. The analysis and controller 1010 also plays a role of defining a configuration format when recording the corresponding information.

More specifically, the controller 1010 controls to record the channel measurement information according to at least one criterion of the presence or absence of the serving cell and the measurement of the neighboring cell. In addition, the controller 1010 controls to record the measurement result for the serving cell and the neighboring cell when the serving cell exists. The controller 1010 records ECUT (EUTRAN Cell Global Id) of the serving cell in the channel measurement information.

 On the other hand, when the serving cell does not exist, the controller 1010 sets information on the serving cell signal strength that is less than or equal to a predetermined reference value when the serving cell signal strength is less than or equal to a predetermined reference value through a serving cell member indicator 1. If the serving cell signal strength is greater than or equal to a predetermined reference value, it is determined whether the measured serving cell is an access inhibited cell. According to the determination result, when the measured serving cell is an access inhibited cell, the controller 1010 controls to set the information on the access inhibited cell through an access inhibited cell indicator 2. The controller 1010 records the EUTRAN Cell Global Id (ECGI) for any of the neighbor cells in the channel measurement information.

Subsequently, the controller 1010 may record the number of detected cells when performing the measurement, and may set information on whether to measure the neighboring cell when performing the measurement through the neighbor cell measurement indicator 3.

According to another embodiment of the present invention, when the controller 1010 records channel measurement information, the controller 1010 records measurement results of n cells having the best signal strength among the cells detected during the measurement, and records ECGI (EUTRAN Cell) among the n cells. Global Id) can record the ECGI for the cell that is successfully acquired. In this case, the controller 1010 may set information on whether a serving cell exists through a serving cell presence indicator (indicator 4).

Meanwhile, according to an embodiment of the present invention, the controller 1010 may control to report the capability or the current state of the terminal to the base station according to the request of the base station. More specifically, when the controller 1010 receives the battery status report command of the terminal from the base station, the controller 1010 generates a control message including information about the terminal battery remaining amount and the battery consumption for a predetermined time. The controller 1010 transmits the generated control message to the base station.

The controller 1010 according to another embodiment of the present invention may set the recording period differently according to the result of measuring the neighboring cells. That is, the controller 1010 determines whether there is a neighbor cell measurement result, and if there is no neighbor cell measurement result, sets the first period as a recording period for the channel measurement result, and if there is a neighbor cell measurement result, the second period. Can be set as the recording period for the channel measurement result. In this case, the first period may be longer than the second period.

In addition, the controller 1010 according to another embodiment of the present invention may control to record the measurement result when the neighbor cell measurement result is present or the serving cell signal strength is less than or equal to the set reference value. The controller 1010 may increase the counter value when the neighbor cell measurement result does not exist or the serving cell signal strength exceeds the set reference value. The controller 1010 may omit the recording when the counter value is less than or equal to the set value, and control to record the measurement result when the counter value exceeds the set value.

The presence and reason of the serving cell and the presence and reason of the measurement of the neighboring cell are determined to determine the measurement information to be recorded. By the analysis and the controller 1010, the configured measurement information is stored in the buffer 1015.

In addition, the controller 1010 according to an exemplary embodiment of the present invention may obtain location information on the service range by using the location information acquisition unit 1007 and include it in the channel measurement information.

To this end, the controller 1010 may control the location information acquisition unit 1007 to obtain location information of the terminal when the reference signal reception power received from the serving cell is less than or equal to a set reference value. The controller 1010 may control to stop the location information acquisition operation when the reference signal reception power for the serving cell is greater than or equal to the set reference value when the location information acquisition is completed or within a set time. In addition, after stopping the operation of acquiring the location information in the service range, the controller 1010 acquires the location information of the terminal to acquire the location information of the terminal when the reference signal reception power from a specific cell is equal to or greater than a set reference value. ) Can be controlled.

According to another preferred embodiment of the present invention, the controller 1010 may control the terminal to drive the location information acquisition unit 1007 in advance before entering the service range region. The controller 1010 may control to drive the location information acquisition unit 1007 in advance after the terminal enters the service range and before moving to the service area. In this case, since each of the time points at which the position information acquisition unit 1007 is driven in advance has been described with reference to FIG. 9, a detailed description thereof will be omitted.

<Terminal>
1005: Measuring instrument
1007: location information acquisition unit
1010: Analysis and Controller
1015: Buffer

Claims (20)

In the method for recording channel measurement information of a terminal in a mobile communication system,
Receiving channel configuration information for receiving measurement configuration information for measuring the channel from a base station;
A measuring step of measuring a serving cell and a neighboring cell according to the measurement configuration information; And
And recording channel measurement information according to at least one of the measurement of the serving cell and the measurement of the neighboring cell. The method of claim 1, wherein the recording step,
And recording the measurement result of the serving cell and the neighboring cell when the serving cell is present. The method of claim 2, wherein the recording step,
When the serving cell signal strength is less than or equal to a predetermined reference value, when the serving cell is not present, setting information on the serving cell signal strength to be less than or equal to a predetermined reference value through a serving cell member indicator 1;
Determining whether the measured serving cell is an access inhibited cell when the serving cell signal strength is greater than or equal to a predetermined reference value; And
If the measured serving cell is an access inhibited cell, setting the information on the access inhibited cell through an access inhibiting cell indicator (indicator 2). The method of claim 2, wherein the recording step,
And recording an ECUT (EUTRAN Cell Global Id) of the serving cell. The method of claim 3, wherein the recording step,
And recording an ECGI (EUTRAN Cell Global Id) for any one of the neighboring cells. The method of claim 3, wherein the recording step,
Recording the number of detected cells when performing the measurement; And
And setting information on whether to measure the neighboring cell when the measurement is performed through the neighboring cell measurement indicator (indicator 3). The method of claim 3, wherein the recording step,
Recording a measurement result of n cells having the best signal strength among the cells detected in the measurement; And
And recording the ECGI for the cell that successfully acquires an EUTRAN Cell Global Id (ECGI) among the n cells. The method of claim 7, wherein the recording step,
And setting information on whether a serving cell exists or not through a serving cell presence indicator (Indicator 4) during the measurement. The method of claim 1, wherein before receiving the channel configuration information,
And reporting the capability or the current status of the terminal to the base station in response to a request of the base station. The method of claim 9, wherein reporting the current state comprises:
Receiving a battery status report command of a terminal from a base station;
Generating a control message including information on the remaining battery capacity of the terminal and the battery consumption for a predetermined time;
And transmitting the generated control message to the base station. The method of claim 1,
Determining a result of measuring a neighboring cell;
Setting a first period as a recording period for a channel measurement result when there is no neighbor cell measurement result; And
Setting a second period as a recording period for a channel measurement result when the neighbor cell measurement result is present;
And the first period is longer than the second period. The method of claim 11,
And receiving from the base station a measurement setup message including recording period information for the first period and the second period. The method of claim 1, wherein the recording step,
And recording the measurement result when the neighboring cell measurement result is present or the serving cell signal strength is equal to or less than the set reference value. The method of claim 13, wherein the recording step,
Increasing a counter value if there is no neighbor cell measurement result or if the serving cell signal strength exceeds a set reference value; And
And skipping the recording when the counter value is less than or equal to the set value, and recording the measurement result when the counter value exceeds the set value. The method of claim 1,
After the measuring step further comprises the step of obtaining location information for obtaining location information for the service range region,
The recording step further includes the step of including the position information for the obtained service range region in the channel measurement information. The method of claim 15, wherein the obtaining of the location information comprises:
An acquiring step of acquiring position information of the terminal when a reference signal received power received from a serving cell is equal to or less than a set reference value; And
And stopping the location information acquisition operation when the reference signal reception power for the serving cell is greater than or equal to the set reference value when the location information acquisition is completed or within a set time period. . The method of claim 16, wherein the obtaining of the location information comprises:
And after the position information acquiring operation is stopped, acquiring the position information of the terminal when the reference signal reception power from a specific cell is equal to or greater than a set reference value. The method of claim 16, wherein the obtaining of the location information comprises:
Before the acquisition step,
And driving, by the terminal, a location information acquisition module before entering the service range region. The method of claim 17, wherein the obtaining of the location information comprises:
Before the interruption step,
And driving the location information acquisition module after the terminal enters the service range and before moving to a service area. An apparatus for recording channel measurement information in a mobile communication system,
A measuring device for measuring a serving cell and a neighboring cell;
The measuring device is controlled to measure the serving cell and the neighboring cell according to the channel configuration information received from a base station, and records the channel measurement information according to at least one of the measurement of the serving cell and the measurement of the neighboring cell. A controller for controlling to; And
And a buffer for storing the recorded channel measurement information.

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